Actions: Run apt-get update before install

[wandernauta]

This resolves an issue where the GitHub Actions CI implementation was not able to find libpoppler/poppler-utils:

Err:30 mirror+file:/etc/apt/apt-mirrors.txt noble-updates/main amd64 libpoppler134 amd64 24.02.0-1ubuntu9.8
  404  Not Found [IP: 52.252.75.106 80]
Ign:35 https://security.ubuntu.com/ubuntu noble-updates/main amd64 poppler-utils amd64 24.02.0-1ubuntu9.8
Err:35 mirror+file:/etc/apt/apt-mirrors.txt noble-updates/main amd64 poppler-utils amd64 24.02.0-1ubuntu9.8
  404  Not Found [IP: 52.252.75.106 80]
E: Failed to fetch mirror+file:/etc/apt/apt-mirrors.txt/pool/main/p/poppler/libpoppler134_24.02.0-1ubuntu9.8_amd64.deb  404  Not Found [IP: 52.252.75.106 80]
E: Failed to fetch mirror+file:/etc/apt/apt-mirrors.txt/pool/main/p/poppler/poppler-utils_24.02.0-1ubuntu9.8_amd64.deb  404  Not Found [IP: 52.252.75.106 80]
E: Unable to fetch some archives, maybe run apt-get update or try with --fix-missing?